1. Field of the Invention
The present invention relates to a touch display device, and especially to a touch display device able to reduce the visibility of a metal pattern.
2. Description of Related Art
Recently, with the development trend of user-friendly operation and simplicity, touch display devices with a panel are becoming more and more widely used in life. Since the user can input signals directly by hands or other objects to access the touch display device, the user's dependence on other input devices (such as a keyboard, a mouse, a remote controller and so on) are thus reduced or even eliminated, thereby greatly facilitating the user's operation.
The touch panel technique may be divided into capacitive and resistive types according to signal generating mechanisms. A capacitive touch panel employs a transparent indium tin oxide (ITO) as a sensing electrode arranged on a transparent substrate along the directions of vertical axis and horizontal axis, and capacitance is generated between the adjacent electrodes in the different axial directions. When a conductor (such as a finger or touch pen) approaches the sensing electrode, it changes the capacitance, thereby generating the tough signal. On the other hand, a resistive touch panel comprises two electrode layers, and dot spacers are disposed between the two electrode layers to insulate the two electrode layers. The two electrode layers are electrically connected when a pressure is applied by a touch of an object, thus generating a signal representing the potential difference, which is then transferred to a controller by a circuit to process and calculate the coordinate position of the touch spot.
Generally, the touch unit of the touch panel comprises a sensing electrode array having a plurality of sensing electrodes arranged along vertical and horizontal directions, bridge metal for electrically connecting the sensing electrodes, and an insulating layer disposed therebetween. However, in the display area, the opaque bridge metal reflects the external light into human eyes. Therefore, the user may easily observe the bridge metal in the touch device, resulting in a poor visual effect of the touch panel display. In addition, as the size of the touch panel increases, manufacturers face the problem that resistance of the sensor electrode is too high to drive the touch panel.
Accordingly, what is needed is to develop a touch display device capable of reducing the visibility of the metal pattern to improve the visual quality of the touch display device, and alleviate the problem of overly high resistance.